Electric regulation



Jan. 15, 1935. J. CREVELING 1,937,992

ELECTRIC REGULATION Filed July 16, 1929 INVENTOR:

Patented Jan. 15, 1935 UNITED STATES PATENT OFFICE ZOClnlms.

m invention pertains broadly to that class of electric regulation wherein a regulating function is to be automatically performed or affected by changes in current in a circuit, and has for a more particular object to provide means for varying the efiect of current changes upon the regulating function so as to cause the said changes to have various regulating increments or decrements, depending upon the value of current in the circuit at the time the fluctuations take place. A further object of my invention is to provide a system of regulation wherein effects of current may be multiplied by static means, and wherein current changes of constant sign may, when desired, be used to produce reverse effects. A further object of my invention is to produce a regulating eiIect when current in a circuit varies while either below or above a certain value, and no regulating eifect as long as it remains at this value or while at zero value. A more specific object of my invention is to provide a system with means for maintaining constant voltage throughout changes tending to take place therein and means for adjusting the value of voltage held throughout said changes by said means, which shall be unaifected when a certain current is flowing in a circuit and become aiiected upon departure of current from said value in either direction. Another object of my invention is to produce an inexpensive type of apparatus which may be employed to accomplish the above objects and which may be readily applied to various types of regulating systems now in use. Other objects will be obvious to those skilled in the art from the following description of the several embodiments of my invention here shown.

In the drawing, Figs. I to VI, inclusive, diagrammatically indicate systems employing various embodiments of my invention, chosen for illustration merely; while Figs. VII and VIII illustrate, in further detail, one type of device I employ in the practice of my invention. Fig. II is a diagram of an arrangement similar to the conventional Wheatstone bridge diagram, which is employed merely for the purpose of aiding in the explanation of my invention on account of its universally known properties.

In Fig. I, 1 represents a suitable source of electrical potential difierence indicated, for

cated as attracting the armature 8, pivoted as at 9, and normally under the influence oi the spring 10, tending to compress the pile 5 and lower its resistance. The coil 8 is indicated as in shunt across the leads 2 and 3, through a suitable resistance 7 which may be adjustable, as indicated. Further description or this portion of the system indicated is omitted, as many types of systems with voltage regulation are now in common use which may be used to fulfill the functions of the parts 1 to 10. A regulator of a type which may be easily compared with the diagrams herein is shown in Patent 1,914,909, granted to me June 20, 1933. The load, which may be of any suitable nature, is indicated as comprising two portions, at L and L, and the current supplied to L returns to the generator through the portion of lead 3 having therein a responsive device indicated, in this instance, as composed of carbon blocks 12 and 13 connected by wires 14 and 15, and so disposed and connected into lead 3 that the current returning to the generator divides and flows through two parallel paths 14-12 and 13-15. The regulating device comprising coil 8 is also affected by the energization of coil 11, which is connected across the parallel paths of the return current as by wires 16 and 17, as and for the purposes hereinafter pointed out.

In Fig. II, the numerals 1-10, inclusive, indicate the same parts as shown in Fig. I, or their equivalents, and a load across the mains is indicated at 18 in the form of lamps, and a second load is indicated at 19 in the form of a storage battery, the current to which passes through the variable resistance or regulating device 20, which is operated by a voltage coil .21 (responsive to changes in voltage upon the battery circuit brought about by 20) and a coil 22 corresponding to coil 11 of Fig. I, and across the device 12-15 in a similar manner; while the device 12-15 is in series with this load as it is with load L in Fig. I.

In Fig. III, the numerals 1-to 11, inclusive, indicate the same instrumentalities as in Fig. I, or equivalents, while two difierent loads are indicated in the form of storage batteries at 24 and 24. It is here assumed that the loads require diflferent current values or that the voltage upon the leads shall be diflerently aflected by like changes in load current values. On this account, a switch indicated at 23 is employed and so arranged that when the load 24 is across the mains, as shown in the figure, the coil 11 is connected across the device 12-15, as in Fig. I; and when governed by suitable mechanism (not shown) controlled by the core of magnetic material 29. This core is operated by the coil 30 across the generator and the coil 31 across the device 12-7-15 which carries the loads indicated -at 26 and 28, while a load having no effect on this device is indicated at 27.

In Figs. V and VI, the individual systems are shown as supplied with power which may be assumed to be of substantially constant voltage,

. furnished by a generator 32-33, feeding the mains 34 and 35, as for example a central station system of usual type.

In Fig. V, the load indicated as a storage battery 39 is assumed to require a higher voltage than that supplied across the leads 34-35, and a booster is employed to raise the voltage upon the load circuit. This comprises the motor 36, illustrated as a' plain shunt machine, for sake of simplicity, which operates the generator 37 having a shunt field winding 40 which has its exciting current controlled by the device indicated as a carbon pile at 41. 42 is a coil across the load circuit which tends to aifect the pile 41 to hold constant voltage upon the load, and 43 is a coil across the device 12-45 tending to afiect the operation of the pile 41 in response to load current.

Fig. VI portrays a 'systern wherein the motor 44, taking power from the mains 34 and 35, operates the generator 45 which supplies the load indicated at 56, or 'such'other load as may be thrown across the leads 51-52. The voltage 'of the generator 45 is controlled by pile 4'7 in series with the field 46, in. the same manner as in Fig. V. v

In Fig. VII, the responsive device 12-15 of the above Figs. Ito VI, inclusive, is shown on a larger scale and of a form that I have found very satisfactory, in the practice of my invention, for loads of reasonable size; and, if this be considered as a front elevation, then a bottom plan and partial section are shown in Fig. VIII.

In these figures, the carbon plates'are of oblong shape and relatively thin, soas to expose considerable heat radiating surface, and are, of course, of ample carrying capacity for the current to be employed. These plates are perforated and the screws 54 provided with washers 55 and 56, and nuts .57 are so arranged with respect thereto as to form good electrical connections with the plates, as shownin Fig. VIII. I'Ihe wires 14 and 15 are usually made of iron, of proper size to carry the load and of proper length to have the resistance required, as will be pointed out. These wires are bent at the ends to form eyes which pass over the ends of screws 54, and when in place are held flrmlyin electrical connection with the screws and plates by means of nuts 58; The device is thus connected in circuit, as indicated, in Figs. I to VI above, by connecting the proper wires thereto, as by means of connectors, as

shown in Fig. VIII, firmly held in p lace by nuts 59. The resistanceof theplates 12 may readily be adjusted within certain limits by means of saw slots, as indicated in dotted lines at 53.

In Fig. IX, there is shown the conventional diagram of a Wheatstone bridge, wherein the current is assumed to enter by way of 60 and leave by way of 61, as indicated by the arrows. It will, of course, be clear that the familiar work- In this-ing formula gR=x1 employed with this layout, follows from the relation A:B::R:X, when the bridge is in balance and the galvanometer current is zero. In other words, the galvanometer current will be zero and the bridge balanced when A:B: :RzX, which may result from an infinite number of values from which an indefinite number may be chosen, in practice, to perform the results required, provided the system be properly proportioned. Now, with current flowing through this arrangement, heat will be developed in each arm, as each has some resistance; and, if B and R be of carbon or other material having a negative temperature coeflicient, the resistances of these arms will fall as the current therethrough increases, tending to cause current to flow through G, inthe direction of the dotted arrow, unless the resistances of A and X suffer a compensating change. Further, by making A and X of material having a positive temperature coeflicient, a reverse effect may be produced by heat tending to increase the current through G, in the direction of the dotted arrow or in the same direction as caused by heating B and R. Thus, the heating efiect of current through the arrangement may be caused to increase the current through the circuit of G in greater proportion than the current through 60-61 increases, and a multiplying effect produced, particularly if A and X be of iron and approach the critical temperature" of this material. That is, with the bridge in balance, and AzB: :RzX, then AX=*"BR, and a change in the value of AX or BR will throw it out of balance and cause current to flow through G; and we have here considered not only that the product BR has been decreased and the product AX increased, so as to unite their eifects in unbalancing the bridge, but that the individual factors of each product have suffered these changes, and a multiplying effect brought about. If, now, we assume that the resistances of the'bridge arms are such as to balance the bridge when their temperatures correspond 'to a certain current value through 60-61, then, if this current be increased, the current through G will increase and may be even multiplied, as above pointed out in the direction of the dotted arrow. However, if the current decrease from this value, producing a balance, the arms will all fall in temperature and the resistance of A and X will fall, while that of B'and R will rise, and both these effects willtend to throw the bridge out of balance' in the opposite direction and cause current to flow through G, in the direction of the fullline arrow and reverse the efiectupon the galvanometer or such other proper device as may be used in its stead.

It will, of course, be noted that, in the above, no account has been taken of the current through as the same'would be negligible, if this were a galvanometer in a system employing a reasondotted arrow, flows only through the carbon 'bloclrsBandR,andthecurrentthroughG,in

. may be connected in circuit, as indicated at 6061 in Fig. IX, and the remaining two diagonally opposite posts may be connected through a galvanometer or other suitable device, as indicated at G in Fig. IX, and the same results will follow as outlined above with respect to Fig. 11:; and that, if the members 12 and 13 are each of equal resistance and the members 14 and 15 are each of equal resistance, it will be immaterial which diagonally disposed pair of parts is connected in the respective circuits to perform the functions required of the device, provided the device corresponding to the galvanometer G in Fig. IX have its terminals properly connected so as to be affected in the proper direction by the cross current.

The operation of my invention may be understood from the following:

Referring to Fig.1, with zero or any normal load at L, if the load L be zero and the generator be running at ,suilicient speed, a predetermined line voltage may be maintained by proper manipulation of the pressure upon the pile 5 controlling the field current of the generator; and it is assumed that the pressure upon the pile, when the same is controlled by the voltage coil 6 alone, is automatically so manipulated. If the current to load L, through the'device 12-15, be such that the device is in balance, no current will flow in the coil 11 and constant voltage will be maintained by coil 6 at the predetermined value, as though the load L were zero. If, now, the load L, through the device 12-15, be varied in either direction, the device will be unbalanced and current will flow through wires 16 and 17, and coil 11 will come into action to modify the voltage supplied to the line and both loads L and L, in such direction as may be determined by the direction of the winding 11 with respect to the winding 6. Thus, the voltage held upon the system may be adjusted by the current supplied to load L, and this may either be a useful load or a mere regulating load, if desired, as for example a resistance or a counterelectromotive force, which may be adjustable, if desired. Or, the resistance of L may be substantially zero, in which event the device 12-15 would I have a high resistance to save current, and, in

effect, would itself be the total load L. With this arrangement, even metal filament lamps, or ballas in the form of iron or special alloy wires either open or in bulbs, may be used for the elements 14 and 15; and fine carbon rods or grids" or carbon lamps or wire of alloys having a negative temperature coefficient, such as phosphor bronze", may be used for the element 12-13; or a material having zero temperature coefficient, such as advance" wire, may be used for 14-15 or 12-13, provided the remaining elements possess either a plus or minus temperature coefllcient if the long range of the device 12-15 be not required. That is, assuming either 12 and 13 or 14 and 15 to have zero temperature coefficient, and the other to have either a positive or negative temperature coefiicient and balanced with a certain current therethrough, any departure from this value of current will cause current to flow through 11 and, by properly proportioning and connecting this coil, the cross" current therethrough will tend to restore the balancing current through the device 12-15 and correct this departure. Further, this eifect can be greatly increased by giving the members 12 and 13 and 14 and 15 opposite temperature characteristics, as above pointed out. A further very useful property of my invention resides in the fact that, in the usual voltage regulators wherein a spring or weight is balanced by a coil, there is a lag due to inertia, friction, or the work required to perform the mechanical operation of the device, and a fm'ther lag due to magnetic hysteresis of the iron in the structure. The structures here shown will have this reduced or eliminated as the "cross" current of the bridge suffers only a time lag required for the current changes to affect the temperature of the device. In the carbon pile regulators, the work required for operation may be reduced to a minimum, and, in practice, may, in many instances, be neglected; but the hysteresis still remains and the elasticity of the pile itself affects the operation in a manner which my invention thus tends to rectify.

Further, in the usual regulator without the coil 11, as the voltage of the generator rises upon starting up and approaches the normal, the resistance of the pile will be somewhat increased by the effect of coil 6, and this is often appreciable before the normal voltage is reached. This requires the generator to be operated at a higher speed to even approximate the normal voltage, and, in some cases, causes useless waste in the pile.

With my invention the adjusting device may be so arranged that, as the generator voltage increases upon starting up, the current in coil 11 will flow in such direction as to weaken the effect of coil 6, and this eifect will not fall to zero until the full required voltage is upon the line; and thus, while operating at slightly lower than normal voltage, the coil 6 may be opposed by coil 11 and more pressure exerted on the pile than would be the case if 11 were omitted, thus assisting to keep up the voltage when the speed falls below normal. Further, the temperature effects produced by current flowing through the device 12- 15 will, of course, depend upon the ability of the device to dissipate the heat generated in it, and this will depend upon design and environment of the device.

The system may, therefore, have its operating characteristics determined by designing the device 12-15 to have certain inherent heat dissipating characteristics or by otherwise affecting the heat dissipation as through the medium in which it is immersed. Therefore, if the device 12-15 be so placed as to be affected by the temperature of the generator or a portion of the load, the operation of the system will be adjusted in accordance with these temperatures, and lower voltages held on the line as the generator or said other portion of the load becomes heated, or the reverse if required; and, if placed where aifected by the changes in atmospheric temperature, the system may have its operating characteristics varied in accordance with the weather.

In the system of Fig. II, the regulator indicated at 5-10 will hold constant-voltage upon the leads '2 and 3 and load 18, as long as the generator speed is suiilcient, while the load 19 will have its current controlled by the resistance of pile 20. Coil 21 will tend to hold constant voltage upon the load 19 which will have a certain predetermined value when the current in 22 is zero and the device 12-15 is in balance, and a modified value when the device 12-15 is out of balance and cross" current flows through 22, which will tend to restore the balance by varying the resistance 20. Therefore, assuming-the load 19 to be a storage battery, as indicated, and to be in a discharged state, so that its voltage is so low that the normal voltage held by coil 21 would cause too great a current therethrough, the device 12- 15 may be so arranged as to prevent the current increasing above a predetermined desired value, and any ill effects of too'great a current avoided.

On the other hand, if the voltage of the battery 19 be so near the line voltage that the normal load is not supplied to 19, the device 12-15 will be out of balance in the opposite sense and thecurrent in 22 will tend to raise the voltage .and supply the full load and charge the battery more rapidly than would be the case if 21 were alone operating the pile 20, which is very desirable in some cases. Further, as the battery 19 becomes charged and its voltage rises, this will tend to cut down the current to 19; while the current in 22 will tend to restore it, as above pointed out. And, in as much as this restoring effect isdependent upon difference in potential across diagonally opposite junctions in the device 1215, it must fall as the difference in potential across the other pair of junctions falls, due to the battery voltage approaching that value which 21 acting alone upon pile limits. By properly adjusting the system, 19 may be charged at a higher rate dur ing a certain portion of the approach of the voltage of 19 to that limited by 21 alone, and then cut down to zero more rapidly, which is a desirable effect in many cases.

In the system of Fig. 111, parts 1 to 11 are the same as in Fig. I, or equivalentt, and operate as above pointed out, and two loads are indicated at 24 and 24' as storage batteries. The battery 24 is indicated as being charged and receiving its current through the switch 23 and device 12 15, which is assumed to affect the generator so that the proper load is maintained as nearly as possible under the running conditions of the generator. The battery 24' is assumed to require either a different voltage or a difierent current value, or both, and the device 12'15' is so arranged as to provide for this when the switch 23 is thrown, so as to shift the connection from 24 to 24', in a manner which will be plain from I the drawing.

In the system of Fig. IV, the prime mover shown as an engine 25 is assumed to have its speed controlled, within certain limits, by manipulation of the core 29 by the coils 303l, and to have its speed raised to a certain desired limit when these coils allow 29 to move toward the left, and decreased to a desired limit as the coils move 29 to the right. The coil 30 tends to hold the voltage constant, at a certain value, when there is no load upon the generator and also when any load con:- nected as at 27 is being supplied alone; while the device 1? -l5 and coil 31 modify this voltage to supply proper current values when the loads 26 or 28 are thrown on, and the operation will be plain from the above described operation of these instrumentalities.

In the system of Fig. V, the voltage upon the load 39 is controlled by manipulation of pile 41, operated by coils 42 and 43, and this voltage will be adjusted by the current in the device 12-15, as may be understood from the above description of operation.

In the system of Fig. VI, the voltage is controlled by the pile 47 and coils 48 and 49, and is modified by the current through 12-15, in a manner that will be plain from the foregoing.

From the foregoing it will be noted that I have '7 produced a system wherein either the voltage upon a circuit or the current in a circuit may be quite accurately maintained, since any variation from a pre-selected standard, in either direction, will aflect the regulation of the system in such manner as to tend to restore the pre-sele'cted conditions, and that this is brought about by simple means requiring no moving parts, which means are capable of producing reverse effects upon changes in the current orv voltage in a uniform direction, in a manner that tends to maintain the desired pre-selected value. Further, that owing to the multip eflects brought about upon changes in temperature of the' devices here employed, the system may be properly regulated without the necessity of operating the temperature affected elements at a very high temperature, on which account auseful structure is produced without the deteriorating eifects of high temperature operation.

As this application is directed toward the broad features of my invention, all switch devices and other appurtenances well known in the artand commonly used in systems of distribution have been purposely omitted as having no bearing upon the broad subject-matter here claimed, it being obvious that any such devices as are now well known in the art may be employed in connection with my invention in practical operating systems. A system employing types of suchdevices is illustrated in Patent 1,915,295, granted to me June 27, 1933.

Idonot wishinanywaytolimit myselftoany of the exact constructions or details of operation here explained merely to point out embodiments of my invention, for it will be obvious that wide departure may be made in the way of apparatus and modes of operation without departing from the spirit and scope of my invention which is as set forth in the following claims:

1. An electric regulator comprehending a plurality of electro-responsive means and one of which may operate the same unaided, thermoaffected means causing another thereof to cooperate with said one to afiect the regulator under predetermined conditions only.

2. An electric regulator comprehending operating means tending to preserve a given standard, means adapted to cooperate therewith to modify said standard and static means for affecting the last-named means onhr in response to current variations in a circuit above and below a certain useful standard.

3. An electric regulator comprehending operating means tending to preserve a given standard, means adapted to cooperate therewith to modify said standard and static means for affecting the last-named means only in response to current variations in a circuit above or below a certain standard and causing reversible effects upon change in current in a uniform direction.

4. An electric regulator comprehending a regulating element, electro-responsive means capable of operating the same to preserve a given standard, another electro-responsive means capable of cooperating therewith in affecting the operation of said element and thermo-responsive static means for determining the operating conditions under which said cooperation shall take place.

5. An electric regulator comprehending a regulating element, electro-responsive means capable of operating the same to preserve a given standard, another ele'ctrc-responsive means capable of cooperating therewith in affecting the operation of said element and thermo-responsive static means for determining the operating conditions under which said cooperation shall take place and reversing the direction of said cooperation.

6. An electric regulator comprehending a regulating element, responsive means capable of operating the same to preserve a given standard, another responsive means capable of cooperating therewith in affecting the operation of said element and static means for determining the operating conditions under which said cooperation shall take place and reversing the direction of said cooperation upon changes in a uniform direction.

'1. An electric regulator comprehending a regulating element, voltage responsive means for operating the same unaided, current affected means adapted to affect said element only when the current therethrough exceeds or falls below a predetermined useful value.

8. The combination with a generator, regulating means for controlling the same and a. storage battery charged by the generator, of means controlling the regulating means in response to voltage variations incident to charging the battery and by current supplied to the battery only when above or below a predetermined value.

9. The combination with a generator, regulating means for controlling the same and a battery charged thereby, of means for controlling the regulating means tending to hold the generator voltage constant and means modifying the generator voltage afi'ected by current supplied to the battery tending to increase the same when below a certain standard. decrease the same when above a certain standard and cause no effect upon the regulating means when the current is at the predetermined standard.

10. An electric regulator comprehending electro-responsive means operative to preserve a given standard, electro-responsive means for altering said standard and thermo-aflected means controlling the effect of said latter responsive means.

11. An electric regulator comprehending electro-responsive means operative to preserve agiven standard, electro-responsive means for altering said standard, and current-carrying thermoafiected means controlling the effect of said latter responsive means and reversing said effect.

12. An electric regulator comprehending electro-responsive means operative to preserve a given standard, electro-responsive means for altering said standard, and static means modifying the efiect of said latter responsive means in a plurality of senses depending upon temperature eifects upon said static means.

. 13. An electric regulator comprehending electro-responsive means operative to preserve a given standard, electro-responsive means for modifying said' standard, and thermo-eifective means controlling the effect of said latter responsive means to cause the same to be elective in a certain direction under certain conditions, and in an opposite direction under other conditions,

14. An electric regulator comprehending electro-responsive means operative to preserve a given standard, electro-responsive means for altering said standard, and static means controlling the efi'ect of said latter responsive means and causing the same to be ineffective and operative in difierent senses in response to current changes in a uniform direction.

15. An electric regulator comprehending electro-responsive means operative to preserve a given standard, electro-responsive means for altering said'standard, and current aflected static means controlling the eflect of said latter responsive means and causing the same to alter said standard in a predetermined manner disproportionate with respect to the current changes aftecting the static means.

16. A battery charging arrangement comprising a dynamo connected in circuit with a storage battery, a field regulator for said dynamo, an electro-magnet provided with two windings controlling'said field regulator, and a Wheatstone bridge in series with the battery and dynamo consisting of two diametrically opposed resistances having a high temperature coeilicient and two other resistances having a low temperature coefilcient, the ends of one of the windings of the electromagnet being connected across two arms of said Wheatstone bridge, whereby said winding may be influenced by the passage of the charging current through the resistances and the other winding being connected at the terminals of the dynamo.

1'1. A battery charging arrangement comprising a dynamo connected to a storage battery to be charged, a field regulator for said dynamo, an electro-magnet provided with two windings controlling said field regulator, one of the windings of said electro-magnet being energized by the battery charging current, and the other winding under the influence of the voltage across the terminals of thedynamo, and associated resistances carrying the battery charging current and having different temperature coefilcients for causing the first winding to oppose the magnetic action of the second winding until a battery charging current of a certain mean value is reached, while on exceeding this mean value of the charging cur-' rent the first winding is caused to add its magnetic action to that of the second winding.

18. An electric regulator including a regulating element, voltage responsive means capable of. operating the same unaided, and current responsive means for affecting said element tending to do so only and whenever the current therethrough is above or below a certain finite standard.

19. The combination with a generator, regulating means for controlling the same and a storage battery charged by the generator, of means controlling the regulating means in response to voltage variations incident to charging the battery and by current supplied to the battery only and whenever. above or below a predetermined value.

20. Means for controlling the operation of a generator having a field winding, said means including two magnet coils at times serving together to affect the value of current in said field winding, and heat affected means rendering one of said coils efiective or ineifective so to function dependingupon the eflect of temperature chanses upon said heat affected means.

JOHN L. CREVELING. 

